When producing rubber compositions, it is common to utilize fillers for the purpose of reducing costs by replacing higher priced constituents of the rubber composition with less expensive constituents that may impart some additional functionality to the final rubber product. In order to achieve these advantages, the use of additives in combination with the fillers is often necessary. For example, German Publication No. DE 3010113, issued to Chemische Werke Huels AG, discloses the use of a poly(butadiene) as couplers for mineral fillers in polymers. Another German patent, DE 3129082, granted to the same company discloses a silane grafted poly(butadiene), which is used as couplers for inorganic fillers. An issued Japanese patent, JP 62265301, to Nippon Soda Co. describes the preparation of a silane-grafted poly(butadiene) used as a surface treating agent for mineral fillers.
Fillers that do not, by themselves, improve the mechanical properties of the rubber composition may be combined with dispersing and coupling agents to improve such properties. The dispersing and coupling agents physically or chemically interact with the polymer matrix and the filler at the boundary between the two phases and have the potential to impart improved physical properties to the rubber composition. For example, U.S. Pat. Nos. 4,381,377 and 4,396,751 disclose homo- or copolymer of a 1,3-diene bound to reactive silyl groups to form a crosslinked product having an improved modulus and curing rate. Therefore, some research has been concentrated on the potential use of such dispersing and coupling agents.
By manipulating rubber compositions, specific advantageous physical properties for tires made from such compositions is of particular interest for tire manufacturers. Reducing fuel consumption may be obtained by developing tires having a very low rolling resistance combined with excellent grip properties and handling behavior. This can produce significant cost and environmental benefits because improved physical properties of the tires can reduce fuel consumption. Accordingly, there is a constant need for improved dispersing and coupling agents that will reduce manufacturing costs and produce rubber compositions having advantageous physical properties, including wet traction, improved rolling resistance, and low temperature performance.